This page has two modes: Live Simulation Playground lets you test controller presets and hardware imperfections. Hardware Replay Evidence shows measured fw0.9.8 HIL runs from the real one-axis testbed.
Pick an angle, press Run, and use Reset to restart the live simulation.
One-Axis Attitude Scene
Transparent CubeSat body with internal reaction wheel; 2D top-view confirms yaw angle.Hardware-effect view — teaching approximation (not measured replay).
In a reaction-wheel ADCS, accelerating the wheel one way produces an opposite torque on the spacecraft body. This view is a teaching visualization; replay data remains the measured evidence.
Press Run to start the simulation and load the attitude scene.
Ready to run: oscillation demo
- ✓ Controller: Aggressive / overshoot demo
- ✓ Target: +30°
- ✓ Hardware effect: Twisted sling / restoring torque
- ✓ Press Run to see overshoot, correction, and settling
- Select a quick target angle, or keep the default.
- Press Run simulation.
- Press Reset simulation to restart.
For a calmer response, switch to Balanced PD in Advanced controls.
Quick target angle
Quick controls
Controller
Aggressive / overshoot demo
Kp 1.80 · Ki 0.000 · Kd 0.08
Target
+30°
Classroom default step
Session
Preparing…
Open Advanced to change presets
Hardware effect
Twisted sling / restoring torque
Stronger torsional pull toward neutral — body may drift back after target crossing.
Observe: Closest-approach error matters; watch post-crossing drift toward neutral.
Advanced controls — all presets, targets, imperfections, manual ticks
Simulation presets
Session will start when you press Run.
Hardware imperfections
Hardware-effect presets — teaching approximations layered on the simulator. Not flight-grade dynamics. Hardware Replay Evidence remains the measured hardware record.
Twisted sling / restoring torque
Teaching approximationStronger torsional pull toward neutral — body may drift back after target crossing.
What to observe: Closest-approach error matters; watch post-crossing drift toward neutral.
Telemetry charts
Hardware-effect view — teaching approximation. Backend simulator physics are ideal; imperfections are a frontend layer for classroom discussion.
Press Run simulation to populate charts.
Target vs actual angle (°)
Angular rate (°/s)
Wheel RPM
PWM command
Battery SOC % (mission model)
Power & generation (mission model)
What to observe
- Overshoot — does actual angle pass the target before settling?
- Settling time — how long until error stays small
- Steady-state error — residual gap after the transient
- Wheel effort — RPM magnitude during the maneuver
- PWM saturation — command pegged high suggests effort limits
- Effect of Kp / Kd / Ki — compare presets on the same target step
- Hardware imperfections — teaching approximations on top of ideal simulator physics
First run
- Press Run simulation.
- Watch the reaction wheel spin.
- Watch the CubeSat yaw in response.
- Notice the actual body move relative to the target ghost.
- Observe overshoot and settling in the chart.
What to try first
Sequence 1 — First run
- Aggressive / overshoot demo
- +30°
- Twisted sling / restoring torque
- Press Run simulation
Observe: Visible overshoot and oscillation, then correction and settling; compare actual body to amber target ghost.
Sequence 2 — Overshoot demo
- Aggressive / overshoot demo
- −30°
- Twisted sling / restoring torque
Observe: Overshoot and correction; body may drift back toward neutral after crossing.
Sequence 3 — Hardware imperfection demo
- Balanced PD
- +30°
- Center-of-mass offset or Motor deadband + lag
Observe: Bias, slower response, asymmetric behavior between directions.
Sequence 4 — Research link
- Switch to Hardware Replay Evidence
- Select CAPRELP or CAPRELM run
- Compare with Real HIL-lite asymmetry in playground
Observe: Learned pulse and best error from measured hardware; replay is evidence, playground presets are approximations.